Note: Descriptions are shown in the official language in which they were submitted.
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METHOD FOR TREATII~TG RENAL DISEASE
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001) This application is a continuation-in-part application of U.S. patent
application
11/229,241 filed on September 16, 2005, which claims the benefit of U.S.
provisional application
60/610,465, filed on September 16, 2004. Both prior applications are herein
incorporated by
reference in their entirety.
STATEMENT REGARDING FEDERALLY
SPONSORED RESEARCH OR DEVELOPMENT
100021 This invention was made with United States government support awarded
by the
following agency: NIH HL-36279. The United States has certain rights in this
invention.
BACKGROUND OF THE INVENTION
[0003] Diabetes and hypertension are the leading causes of end-stage renal
disease (ESRD).
Despite effective medications, compliance and drug costs are serious problems
and only a small
percentage of patients achieve adequate life-long control of blood pressure or
their diabetes. As a
result, the incidence of ESRD is increasing as the population ages and becomes
more obese. The
cost to the U.S. federal government for the treatment of ESRD exceeds 15
billion dollars a year.
[0004] Current treatment options for ESRD include kidney dialysis and
transplant. In addition
to the high cost associated with these two treatments, dialysis only provides
filtration but not other
functions of the kidney and kidney transplant has the problems of organ
shortage and rejection.
[0005) Recently, TGF-(3 has been identified as a target for treating diabetes-
and hypertension-
induced nephropathies since TGF-(3 expression has been found to be upregulated
in kidney in
patients and animal models of these diseases (Noble NA and Border WA, Sem
Nephrol 17:455-466,
1997; Reeves WB and Anderoli TE, Proc Natl Acad Sci 97:7667-7669, 2000; Sharma
K and
McGowan T. Cytokine Growth Factor Rev 11:115-123, 2000; Sharma K et al.,
Diabetes 46:854-859,
1997; Yamamoto T et al., Proc Nat'l Acad Sci 90:1814-1818, 1993; Yamamoto T et
al.; Kidney Int
49:461-469, 1996). Diabetes- and hypertension-induced nephropathies are
characterized by the early
development of proteinuria which accelerates the progression of renal disease
by, for example,
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promoting the development of glomerular lesions (e:g., glomerulosclerosis),
and TGF-0
overexpression is believed to be a critical factor in this process (Dahly AJ
et al., Am JPhysiol Regul
Integr Cornp Physiol 283:R757-767, 2002; Border WA et al. NEngl Jhled 331:1286-
1292, 1994;
Sanders PW Hypertension 43:142-146, 2004; McCarthy ET et al., JAm Soc Nephrol
14:84A, 2003;
Bottinger EP et al., JAm Soc Nephrol 10:2600-2610, 2002; August P et al.,
Kidney Int Supp187:S99-
104, 2003; Ziyadeh FN et al., Proc Nat'Z Acad Sci USA 97:8015-8020, 2000; 175,
202, 218, 265,
266). For example, TGF-0 has been found to directly increase the permeability
of isolated glomeruli
to albumin (Sharma R et al., Kidney Int 58:131-136, 2000), indicating a direct
role of TGF-(3 in the
induction of proteinuria. TGF-0 has also been found to increase the production
of extracellular
matrix and promotes the development of glomerulosclerosis and renal
interstitial fibrosis (Pavenstadt
H et al_, Physiol Rev 83:253-307, 2003; Border WA et al. NEngl JMed 331:1286-
1292, 1994; and
Sanders PW Hypertension 43:142-146, 2004). Importantly, blocking the activity
of TGF-j3 by either
TGF-0 antibodies or antisense oligonucleotides has been shown to reduce the
degree of proteinuria
and glomerular damage (Dahly AJ et a1., Am JPhysiol Regul Integr Comp Physiol
283:R757-767,
2002; Ziyadeh FN et al., Proc Nat'l Acad Sci USA 97:8015-8020, 2000; Chen s et
al., Biochem
Biophys Res Commun 300:16-22, 2003; and Han DC et al., Am JPhysiol 278F628-
F634, 2000).
[0006] Increased TGF-P expression in kidney is also associated with kidney
transplantation
rejection (Shihab FS et al. Kidnev Int 50:1904-1913, 1996; Shihab FS et al.,
JAm Soc Nephrol
6:286-294, 1995), various forms of glomerulosclerosis (Yamamoto T et al.,
Kidney Int 49:461-469,
1996; Yoshioka K et al., Lab Invest 68:154-163, 1993), Heyman nephritis
(Shankland SJ et al.,
Kidney Int 50:116-124, 1996), remnant kidney (Lee L et al., J Clin Invest
96:953-964, 1995; Wu LL
et al., Kidney Int 51:1553-1567, 1997), ureteral obstruction (Kaneto H et al.,
Kidney Int 44:313-321,
1993), kidney diseases caused by radiation and immunosuppressive and
nephrotoxic drugs such as
cyclosporine, puromycin, cisplatin, and heavy metals (Oikawa T et al., Kidney
Int 51:164-172, 1997;
Sharma VK et al., Kidney Int 49:1297-1303, 1996; Shihab FS et al. Kidney Int
49:1141-1151, 1996;
Jones CL et al., Am JPath 141:1381-1396, 1992;1Via LJ et al. Kidneylnt 65:106-
115, 2004), and
every animal model of renal injury that has been examined (Noble NA and Border
WA, Sem Nephrol
17:455-466, 1997). Blocking TGF-(3 activity by its antibodies provided
beneficial effects in
cyclosporine- and puromycin-induced nephropathies (Ling H et al., JAm Soc
Nephrol 14:377-388,
2003; Ma LJ et al. Kidney Int 65:106-115, 2004).
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[0007] The mechanism by which TGF-(3 initiates the development of proteinuria
and renal
injury is not clear. Identifying downstream respondents of TGF-(3 in this
regard will provide
additional and novel targets for the treatment of renal diseases associated
with elevations in the
expression of TGF-J3 in the kidney.
BRIEF SUMMARY OF =THE INVENTION
[0008] The present invention provides a method for preventing or treating a
renal disorder in a
human or non-human animal by administering 20-hydroxyeicosatetraenoic acid (20-
HETE) or an
agonist thereof to the human or non-human animal in. an amount sufficient to
prevent or treat the
renal disorder.
[0009] The present invention further provides a method for preventing or
treating ischemic
acute renal failure in a human or non-human animal by administering 20-HETE or
an agonist thereof
to the human or non-human animal in an amount sufficient to prevent or treat
ischemic acute renal
failure.
[0010] The present invention further provides a method for preventing or
reducing the severity
of damage to an ex vivo preserved kidney upon reperfusion by preserving the
kidney ex vivo in a
storage solution that contains 20-HETE or an agonist thereof in an amount
sufficient to prevent or
reduce the severity of damage to the kidney upon reperfusion.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0011] Fig. 1 shows the expression of TGF-0 1 in'the kidney of Sprague Dawley
(SD) and Dahl
S rats (a genetic model of salt-sensitive hypertension and hypertension-
induced renal disease) fed an
LS and HS for 7 days. Renal homogenates isolated from SD (lanes 1-3), Dahl S
rats fed an LS diet
(lanes 4-7), and Dahl S rats fed an HS diet (8% NaC1) for 7 days (lanes 8-11).
Each lane was loaded
with a homogenate (30 g protein/lane) isolated from different animals (n=3 to
4 per group). *
Indicates a significant difference versus the values seeri in Dahl S rats fed
an LS diet. HS-7, HS diet
for 7 days.
[0012] Fig. 2 shows the effect of an HS diet and the role of TGF-(3 on
permeability to albumin
(Palb) in glomeruli isolated from SD rats and Dahl S rats fed an LS and HS
diet for 7 days or in Dahl
S rats fed an HS diet that were treated with a TGF-0 Ab (1D11-7). The TGF-(3
Ab used effectively
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neutralizes all three isoforms of TGF-0. Glomeruli were preincubated with
vehicle or 10 ng/ml of
TGF-01 for 15 minutes at 37 C and Palb was measured. Numbers in parentheses
indicate the number
of glomeruli and number of rats studied per group. *'Indicates a significant
difference versus the
values seen in Dahl S rats fed an LS diet. f Indicates a significant
difference from the corresponding
control value. HS-4, HS for 4 days. HS-7, HS for 7 days.
[0013] Fig: 3 shows the effects TGF-J31 (10 ng/inl) on production of 20-HETE
by isolated
glomeruli. A representative LC/MS chromatogram is presented in Panel 4A. TGF-
[il inhibited the
formation of 20-HETE peak with a m/z of 319 that elutes at a retention time of
16 minutes. Panel B
presents a summary of the results obtained from 6 experiments. t Indicates a
significant difference
from the corresponding control value.
[0014] Fig. 4 shows the effects a 20-HETE agoriist on the changes in Palb
produced by TGF-01.
Glomeruli were pre-incubated with vehicle or TGF-(31 (10 ng/ml) for 15 minutes
at 37 C and
changes in Paib were determined. Glomeruli were pretreated with a stable 20-
HETE agonist, 20-
hydroxyeicosa-5(Z), 14(Z)-dienoic acid (WIT003), for 15 minutes at 37 C and
the Palb response to
TGF-0 1 (10 ng/ml) was redetermined. Numbers in parentheses indicate the
number of glomeruli and
number of rats studied per group. j Indicates a significant difference from
the corresponding control
value.
[0015] Fig. 5 shows comparison of plasma creatinine concentrations in Sprague
Dawley rats
following 30-minute ischemia and 24 hrs of reperfusion of the kidney. Rats
were treated with
vehicle, a 20-HETE formation inhibitor N-hydroxy-N'-(4-butyl-2-methylphenol)-
formamidine
(HET0016, 5 mg/Kg), or WIT003 (10 mg/Kg) 30 minutes prior to initiation of the
ischemia.
[0016] Fig.6 shows comparison of plasma creatinine concentrations in Dahl S
rats (20-HETE
deficient strain) and 2X4 congenic strain of Dahl S rats that overexpress the
CYP4A genes that make
20-HETE in the kidney following 20-minute ischemia and 24 hrs of reperfusion
of the kidney.
DETAILED DESCRIPTION OF THE INVENTION
[0017] It is disclosed here that upregulation in rerial TGF-P increases
permeability of the
glomerular filtration barrier to albumin and other macromolecules through
inhibiting the glomerular
production of 20-HETE. As such increase in glomerular permeability to albumin
leads to proteinuria
and further to other glomerular injuries (e.g., glornerulosclerosis and renal
interstitial fibrosis), the
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present invention provides new tools for preventing and treating TGF 0-related
renal disorders as
well as physical and pathological manifestations thereof.
[0018] In one aspect, the present invention relates to a method for preventing
or treating a TGF
0-related renal disorder in a human or non-human animal. The method involves
administering 20-
HETE or a 20-HETE agonist to the human or non-human animal in an amount
sufficient to prevent
or treat the renal disorder. By TGF (3-related renal disorder, we mean a renal
disease and physical
and pathological manifestations thereof in which TGF-[3 expression is
upregulated. Examples of
such disorders include but are not limited to proteinuria, nephropathies
induced by diabetes and
hypertension (e.g., salt sensitive hypertension), kidney transplantation
rejection, Heyman nephritis,
remnant kidney nephropathy, ureteral obstruction nephropathy, and kidney
diseases caused by
radiation and immunosuppressive and nephrotoxic drugs such as cyclosporine,
puromycin, cisplatin,
and heavy metals. In one embodiment, the method of the present invention is
employed to prevent or
treat proteinuria or a proteinuria-related renal disorder. By proteinuria-
related renal disorder, we
mean a renal disease in which proteinuria is detected. In another embodiment,
the method of the
present invention is employed to prevent or treat diabetes- or hypertension-
induced nephropathy.
[0019] Examples of 20-HETE agonists that can be used in the present invention
include but are
not limited to those disclosed in U.S. Patent No. 6,395,781; Yu M et al., Eur
JPharmacol. 486:297-
306, 2004; Yu M et al., Bioorg Med Chem. 11:2803-2821, 2003; and Alonso-
Galicia M et al., Am J
Physiol. 277:F790-796, 1999, all of which are herein incorporated by reference
in its entirety. For
example, 20-HETE agonists defined by the following,formula as provided in U.S.
patent 6,395,781
can be used in the present invention:
sp`3 Center.m W-Rl
/
x
sp`3 Centerri Y-Ra
wherein R, is selected from the group consisting of carboxylic acid, phenol,
amide, imide,
sulfonamide, sulfonamide, active methylene, 1,3-dicarbonyl, alcohol, thiol;
amine, tetrazole and
other heteroaryl groups;
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R2 is selected from the group consisting of carboxylic acid, phenol, amide,
imide, sulfonamide,
sulfonamide, active methylene, 1,3-dicarbonyl, alcohol, thiol, amine,
tetrazole and other heteroaryl;
W is a carbon chain (Ci th.rough C25) and may be linear, cyclic, or branched
and may comprise
heteroatoms;
Y is a carbon chain (Cl through C25) and may be linear, cyclic, or branched
and may comprise
heteroatoms; I
sp`3 Center is selected from the group consisting of vinyl, aryl, heteroaryl,
cyclopropyl, and
acetylenic moieties;
X is an alkyl chain that may be linear, branched, cyclic or polycyclic and may
comprise heteroatoms;
mis0,1,2,3,4or5;and
nis0, 1,2,3,4or5.
[0020] Preferably, a 20-HETE agonist defined by the above formula has a
carboxyl or other
ionizable group at either Rl or R2 and contains a double bond or other
functional group at a distance
equal to 14-15 carbons from the ionizable group (U.S. patent 6,395,781). More
preferably, the 20-
HETE agonist contains a length of 20-21 carbons, has a carboxyl or other
ionizable group at either
Rl or R2, contains a double bond or other functional group at a distance equal
to 14-15 carbons from
the ionizable group, and contains a hydroxyl group on the 20 or 21 carbon at
either Rl or R2 (U.S.
patent 6,395,781).
[0021] In one fozm, the present invention contemplates the use of one or more
of the following
20-HETE agonists: 20-hydroxyeicosanoic acid, 20-hydroxyeicosa-5(Z),14(Z)-
dienoic acid
(WIT003), and N-methylsulfonyl-20-hydroxyeicosa-5(Z),14(Z)-dienamide.
[00221 In addition to the beneficial effect on chronic renal diseases
associated with elevations in
renal TGF-0 expression such as proteinuria, diabetes-induced nephropathy, and
hypertension-
induced nephropathy, the inventors also found that treating animals with 20-
HETE or a 20-HETE
agonist was able to reduce acute renal injury caused by ischemia (see example
2 below).
[0023] Ischemia is defined as a poor supply of blood and oxygen to an organ.
When the blood
supply to the kidney is cut off or reduced, the tubular cells undergo necrosis
and apoptosis and acute
renal failure can develop. Ischemia has many causes such as cardiac surgery,
loss of blood, loss of
fluid from the body as a result of severe diarrhea or bums, shock, and
ischemia associated with
storage of the donor kidney prior to transplantation. In these situations, the
blood flow to the kidney
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may be reduced to a dangerously low level for a time period great enough to
cause ischemic injury to
the tubular epithelial cells, sloughing off of the epithelial cells into the
tubular lumen, obstruction of
tubular flow that leads to loss of glomerular filtration and acute renal
failure.
[0024] Acute renal failure refers to a sudden decline of glomerular filtration
rate to a level so
low that little or no urine is formed, and substances that the kidney usually
eliminates remain in the
body. Ischemia causes acute renal failure by reducirig the blood flow to the
kidney, which leads to
inefficient excretion. The reduced blood flow also results insufficient oxygen
supply to the highly
metabolically active renal tubular cells that become depleted of high energy
phosphates and undergo
irreversible ischemic injury leading to necrosis and/or apoptosis. The cells
then rupture or slough off
the basement membrane and obstruct the tubular lumen that then backs up
pressure in the obstructed
tubules and prevents filtration even when and if renal perfusion is restored.
[0025] As 20-HETE is a potent renal vasoconstrictor, it is surprising that 20-
HETE or an
agonist thereof would have beneficial effects on kidneys damaged by ischemia.
Without intending to
be limited by theory, the inventors believe that the beneficial effects of 20-
HETE in preventing renal
ischemic injury is likely due to its effects on the survival of tubular
epithelial cells subjected to an
ischemic insult as 20-HETE has direct effects to inhibit sodium transport in
tubular epithelial cells
and activates many intracellular pathways implicated in cell growth and
survival. In this regard, the
present invention provides a method for preventing or treating ischemic acute
renal failure in a
human or non-human animal by administering 20-HETE and/or a 20-HETE agonist to
the human or
non-human animal in an amount sufficient to prevent or treat ischemic acute
renal failure.
Optionally, the method also involves the step of monitoring kidney function
such as the urine-
forming function wherein treatment with 20-HETE and/or an agonist thereof is
expected to improve
such function. For example, 20-HETE or an agonist thereof can be given to a
patient before, during,
and/or immediately after cardiac surgery or kidney transplantation operation
to prevent or treat acute
renal failure. Examples of 20-HETE agonists, including the preferred ones, are
as described above.
[0026] The present invention is not limited by a:specific route of
administration. Suitable
routes of administration for 20-HETE or a 20-HETE agonist include but are not
limited to oral
administration, intravenous administration, subcutaneous administration,
intramuscular
administration, and direct delivery into the kidney. Optimal dosages of 20-
HETE or a particular 20-
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HETE agonist for preventing or treating a particular,renal disorder via a
particular route of
administration can be readily determined by a skilled artisan.
[0027] 20-HETE and/or an agonist thereof may also be used to preserve a kidney
ex vivo.
Organs that are used for t.ransplanta.tion require effective ex vivo
preservation from the moment the
organ is retrieved to the time of transplantation. Hypothermic preservation
solutions have been
developed to maintain tissue viability by reducing metabolic activity and the
accumulation of toxic
substances during the cold ischemic period. Organs used for transplantation
can undergo lengthy
periods of cold ischemic storage after removal from the blood supply,
resulting in an increased
susceptibility to damage upon reperfusion. In clinical renal transplantation,
prolonged cold storage
has been demonstrated in many studies to be strongly associated with delayed
graft function, which
may affect subsequent short- and long-term graft survival. The present
invention provides a method
for preventing or reducing the severity of damage to an ex vivo preserved
kidney upon reperfusion by
~
preserving the kidney ex vivo in a storage solution that contains 20-HETE
and/or a 20-HETE agonist
in an amount sufficient to prevent or reduce the severity of damage to the
kidney upon reperfusion.
In one embodiment, such amount is from about 0.1 M to about 10 M.
Optionally, 20-HETE
and/or an agonist thereof is also included in one or more of the other
solutions that a kidney will
come in contact with from the time of retrieval to the time of
transplantation. A doctor who will
perform the transplantation operation and/or a patient who will receive the
kidney may be informed
that the kidney has been preserved under the conditions for preventing or
reducing the severity of
kidney damage upon reperfusion.
[00281 The invention will be more fully understood upon consideration of the
following non-
limiting example.
Example 1
20-HETE Agonist Opposes TGF 0-induced Glomerular Injury
[0029] This example shows that transforming growth factor-beta (TGF-(3) alters
the glomerular
permeability by inhibiting the glomerular production of 20-
hydroxyeicosatetraenoic acid (20-HETE).
Renal expression of TGF-[3 doubled in Dahl salt-sensitive (Dahl S) rats fed a
high salt diet for 7 days
and this was associated with a marked rise in permeability to albumin (Palb)
from 0.19+0.04 to
0.75+0.01 along with changes in the ultrastructure of the glomerular
filtration barrier. Chronic
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treatment of Dahl S rats with a TGF-[i neutralizing antibody prevented the
increase in Palb and
preserved the structure of glomerular capillaries proving that hypertension-
induced renal disease is
dependent on increased formation and action of TGF-0. It had no effect on the
rise in blood pressure
produced by the high-salt diet. Preincubation of glomeruli isolated from
Sprague Dawley (SD) rats
with TGF-01 (10 ng/ml) for 15 minutes increased Palb from 0.01+0.01 to
0.60+0.02. This was
associated with inhibition of the glomerular production of 20-HETE from 221+11
to 3.4+0.5
g/30min/mg protein. Pretreatment of SD glomeruli with a stable analog of 20-
HETE, 20-
hydroxyeicosa-5(Z), 14(Z)-dienoic acid, reduced baseline Palb and opposed the
effects of TGF-0 to
increase Palb=
Materials and Methods
100301 Dahl salt-sensitive rat model: Dahl salt-sensitive (S) rats exhibit
many traits associated
with salt-sensitive hypertension in humans (Campese VM. Hypertension 78:531-
550, 1994; and
Grimm CE et al., Hypertension 15:803-809, 1990). They are salt-sensitive
(Iwai, J. Hypertension
9:118-120, 1987; and Rapp J.P. Hypertension 4:753-763, 1982), insulin-
resistant (Reft, GM et al.,
Hypertension 18:630-635, 1991) and hyperlipidemic (Raji, L et al., Kidney Int.
41:801-806, 1984;
and O'Donnell, MP et al., Hypertension 20:651-658, 1992), and they rapidly
develop proteinuria and
glomerulosclerosis when challenged with a high salt (HS) diet (O'Donnell, MP
et al., Hypertension
20:651-658, 1992; Roman RJ et al., Hypertension 12:177-183, 1988; Roman RJ et
al., Hypertension
21:985-988, 1988; Roman RJ et al., Am JHypertens 10:63S-67S, 1997; and Tolins
JP et al.,
Hypertension 16:452-461, 1990). The glomerular lesions that develop resemble
those seen in
patients with hypertension- and diabetes-induced nephropathy (McClellan W et
al., Am JKidney Dis
12:285-290, 1987; Ronstand GS et al., NEngl JMed 306:1276-1279, 1982; and
Tierney WM et al.,
Am JKidney Dis 13:485-493, 1989). The renal expression of transforming growth
factor-(3 (TGF-0)
is elevated in Dahl S rats fed a high salt (HS) diet and that chronic
treatment of Dahl S rats with a
TGF- j3 neutralizing antibody (Ab) for three weeks reduces proteinuria and the
degree of
glomerulosclerosis and fibrosis (Dahly AJ et al., Am JPhysiol Regul Integr
Comp Physiol 283:R757-
767, 2002).
[00311 General: Experiments were performed on'7-week-old Sprague Dawley
(Taconic Labs)
rats fed a normai-salt diet containing 1% NaC1 (#5010, Purina) and Dahl salt-
sensitive/John Rapp
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rats obtained from our colony maintained at the Medical College of Wisconsin.
Rats were fed a
purified diet (AIN76) purchased from Dytes, Inc. that contained either 0.4%
(low salt, LS) or 8.0%
NaCI (high salt, HS). To assess the role of TGF-(3 in altering proteinuria and
Palb during hypertension
development, a group of the Dahl S rats fed a HS diet were treated with an
intraperitoneal injection
of a murine anti-TGF-0 monoclonal Ab (0.5 mg/kg;,IDI1; Genzyme Corp) or a
control murine
monoclonal Ab (13C4; antiverotoxin) every other day (Dasch JR et al., Jlmmunol
10:2109-2119,
1989). At the end of the treatment period, rats were placed overnight in
metabolic cages for
measurement of protein and albumin excretion (Dahly AJ et al., Am JPhysiol
Regul Integr Comp
Physiol 283:R757-767, 2002). They were then anesthetized with halothane, and
the kidneys were
collected for measurement of the expression of TGF-,(3 protein levels by
Western blot (Hoagland KM
et al., Hypertension 43:860-865, 2004) and for glomerular isolation for the
measurement Of Palb and
the production of 20-HETE. Catheters connected to radiotelemetry transmitters
Data Science Inc.)
were implanted into the femoral artery of 10 additional control and 10 1D11-
treated Dahl S rats to
determine the effects of anti-TGF-(3 therapy on the development of
hypertension. Mean arterial
pressure (MAP) was measured for 3 hours per day, between 9 AM and 12 PM,
during a control
period when rats were fed an LS diet and after they were fed an HS diet for 7
days.
[0032] Measurement of Albumin Permeability (P,,ib): Glomeruli were isolated
using the sieving
method described in Sharma R et al. (Kidney Int 58:131-136, 2000) and Savin VJ
et al. (JAm Soc
Nephrol 3:1260-1269, 1992) in a media containing 5 g/dl of bovine serum
albumin (BSA). In each
experimental condition, Palb was determined from the change in glomerular
volume (AV) after
exchange of the bath with medium containing 1 g/dL albumin. Palb was
calculated as 1-
(AVexperimental/AVcontrol), where glomeruli from Sprague Dawley rats fed a
normal-salt diet were used
to provide the control value for each experiment. To verify that lack of AVs
in Dahl S rats were
related to changes in Palb rather than to changes in mechanical properties of
glomeruli, additional
studies were performed in which the glomeruli were exposed to a 5% solution of
high molecular
weight dextran. A change in the size of Dahl S glome'ruli under these
conditions indicates that the
lack of response to 1% albumin was attributable to an increase in Palb (Savin
VJ et al., JAm Soc
Nephro13:1260-1269, 1992).
[0033] In other experiments, we examined the interaction of TGF-(3 and 20-HETE
on PAIb in
glomeruli isolated from Sprague Dawley rats and Dahl S rats fed either an LS
diet or an HS diet for 4
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days. Glomeruli were preincubated with vehicle or TGF-01 (10 ng/ml) for 15
minutes at 37 C and
changes in Palb were determined. Glomeruli were also pretreated with a stable
20-HETE agonist, 20-
hydroxyeicosa-5(Z), 14(Z)-dienoic acid (WIT003; 1; mol/L; Taisho
Pharmaceutical) (Alonso-
Galicia, M et al., Am. J. Physiol. 277:F790-F796, 1999; and Yu, M et al.,
Bioorg. Med. Chem.
11:2803-2821, 2003), for 15 minutes at 37 C and the Palb response to TGF-(31
(10 ng/ml) was
redetermined. A minimum of 5 glomeruli from each rat was studied, and these
experiments were
performed using _ 5 rats per treatment group.
100341 Electron microscopy: Kidneys from Dali1 S rats fed an LS diet and Dahl
S rats fed an HS
diet for 1 week and treated with 1D11 or vehicle were collected and fixed in a
4% glutaldehyde
solution. Thin epon sections were prepared, stained with uranyl acetate and
lead citrate, and
examined at 16,000X using a transmission electron microscope (Hitachi H600).
j00351 Western blots: Homogenates were prepared from the kidneys of control
Sprague Dawley
rats and Dahl S rats fed an LS or HS diet for 7 days. Aliquots of the
homogenates (30 j.tg protein)
were separated on a 12.5% sodium dodecyl sulfate gel, transferred to a
nitrocellulose membrane
incubated with a primary TGF-P 1 Ab (SC:146; Santa Cruz Biotechnology),
followed by a secondary
Ab (SC:2004; Santa Cruz Biotechnology) and developed using enhanced
chemiluminescence as
described in Hoagland KM et al., Hypertension 43:860-865, 2004. Membranes were
poststained
with Commassie blue to normalize results for potential differences in sample
loading.
[0036] Liquid Chromatograph,y/.Mass Spectroscopy measurement ofglomerular 20-
HETE
production: Glomeruli (approximately 20 g protein),were incubated in a 0.1
mol/L KPO4 buffer
containing I mmol/L NADPH for 30 min at 37 C in the presence and absence of
TGF-(3l (10 ng/ml).
Incubations were stopped by acidification with formic acid, homogenized, and
the homogenate
extracted with chloroform:methanol (2:1) after addition of 10 ng of internal
standard, 14,15-
epoxyeicosa-5(Z)-enoic-methyl sulfonylimide (EEZE). Samples were reconstituted
in 50%
acetonitrile, cleaned up using on online reverse-phase high performance liquid
chromatography
(HPLC) trapping column, and then the HETEs and epoxyeicosatrienoic acids
(EETs) in the samples
were separated using an isocratic step gradient on an 1,8C-RP 2X250 mm
microbore BPLC
(BetaBasicl8 150x21 3 m, Thermo.Hypersil-Keystone) using a mobile phase
consisting of
acetonitrile:water:acetic acid (57:43:0.1) for 20 minutes to resolve the HETEs
followed by
acetonitrile:water:acetic acid (63:37:0.1) for 15 minutes to resolve the EETs.
Samples were ionized
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using negative ion electrospray and the peaks eluting with a mass/charge ratio
(m/z) of 319 (HETEs
and EETs) or 323 (internal standard) were isolated and monitored in the
selective ion mass
spectroscopy (MS) mode using an Agilent LSD ion trap mass spectrometer
(Agilent Technologies
1100). The ratio of ion abundances in the peaks of interest (HETEs and EETs,
m/z 319) versus that
corresponding to the closely eluting internal standard (EEZE, m/z 323) were
determined and
compared with a standard curve generated over a range from 0.1 to 2 ng of 20-
HETE and EETs with
each batch of samples.
[0037] Statistics: Mean values + 1 SE are presented. Significance of
differences between mean
values was determined using an ANOVA followed by the Student-Newman-Keuls post
hoc test. A
P<0.05 was considered significant.
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Results
[0038] Effects of high salt diet on the renal expression of TGF /31: The
results of these
experiments are presented in Fig. 1. The expression'of TGF-(31 in the kidney
more than doubled in
Dahl S rats fed an HS diet for 1 week compared with the levels seen in Dahl S
rats fed an LS diet.
[0039] Effects of high salt diet on PRtb: A comparison of Paly in Sprague
Dawley and Dahl S rats
fed=an LS=and HS diet at various times for up to a week are presented in Fig.
2. Baseline Palb was
significantly higher in Dahl S rats maintained on an LS diet than in control
Sprague Dawley rats. Pajb
increased in Dahl S rats fed an HS diet after only 4 days, and it reached a
peak after 7 days. The
increase in PMb in Dahl S rats fed an HS for one week was associated with a
significant rise in blood
pressure from 121 2 to 136+3 mm Hg (n=10) and a marked increase in the
excretion of protein from
47t8 mg/day to 217 31 mg/day (n=14). Similarly, albumin excretion rose from 27
9 mg/day to
129 26 mg/day, after Dahl S rats were fed an HS diet for 7 days.
[0040] Role of TGP-,8 in altering Prr16 in Dahl S rats: A comparison of the
effects of exogenous
administration of TGF-P 1(10 ng/mL) on Paib in glomeruli isolated from Sprague
Dawley and Dahl S
rats is also summarized in Fig. 2. TGF-Pl increased Palb from 0.01=L0.01 to
0.56=L0.02 in glomeruli
isolated from Sprague Dawley rats and from 0.19 0.01 to 0.75 0.01 in glomeruli
isolated from Dahl
S rats fed an LS diet. TGF-(3l also increased in Palb iri Dahl S rats fed an
HS diet for 4 days, but it
had no effect on Palb in Dahl S rats fed an HS diet for 7 days, because the
baseline Palb in these rats
was already near maximal.
[0041] Chronic treatment of Dahl S rats fed an HS diet with a TGF-(3
neutralizing Ab prevented
the increase in baseline Palb. Administration of TGF-(31 to these glomeruli
still increased Palb, similar
to that seen in glomeruli isolated from control Sprague Dawley rats and Dahl S
rats fed an LS diet.
TGF-01 Ab therapy had no effect on the rise in blood pressure. Blood pressure
rose from 123J=4 to
136f3 mm Hg (n=10) in Dahl S rats fed an HS diet that were treated with 1D11
for 7 days.
[0042] Electron microscopy: Electron micrographs of the ultrastructure of
glomerular
capillaries in Dahl S rats fed an LS or HS diet, and in those treated with the
TGF-(3 Ab for 1 week,
were obtained. The Dahl S rats fed an LS diet exhibited a normal appearance of
the glomerular
ultrafiltration barrier. In Dahi S rats fed an HS diet for 7 days, there was a
retraction and fusion of
the foot processes of podocytes and exposure of portions of the basement
membrane. There was also
swelling of the endothelial cells lining the glomerular capillaries, which
changed their shape from a
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flattened to a more cubodial endothelium. These changes in the ultrastructure
of glomerular filtration
barrier in Dahl S rats fed an HS diet were prevented,by administration of the
TGF-(3 Ab.
[0043] Effect of TGF,6 on the glomerular production of 20-HETE: The effects of
TGF-(3 on the
production and metabolism of arachidonic acid (AA) by isolated glomeruli are
presented in Fig. 3.
Glomeruli incubated with AA produced a number of large peaks with an m/z of
319 that coelutes
with 20-HETE, 15-HETE, 12-HETE, 5-HETE and 1,4,15-EET, 11,12-EET, 8,9-EET, and
5,6-EET
standards (Fig. 3A). We further verified that the largest peak that elutes at
16 minutes after
fragmentation produces an MS/MS spectrum with prominent secondary ions at m/z
of 301, 273, 257,
and 245, identical to that seen with a 20-HETE stand i ard. Pretreatment of
glomeruli with TGF-[i 1
selectively reduced the formation of 20-HETE by 97% (Fig. 3B) without
affecting the formation of
15-, 12- or 5-HETE or EETs (Fig. 3A).
[0044] Effects of a 20-HETE agonist on P,,lb: The effect of addition of a 20-
HETE agonist on
the changes in PaIb produced by TGF-01 is summarized in Fig. 4. Pretreatment
of glomeruli with a
20-HETE agonist reduced baseline Paib and greatly attenuated the increase in
Palb produced by TGF-
01. Similar results were obtained with Dahl S rats maintained on an LS diet or
fed an HS diet for 4
days. For example, TGF-(31 increased Paib from 0.5810.04 (n=25 glomeruli; 5
rats) to 0.87+0.02
(n=25; 5 rats) in glomeruli isolated from Dahl S rats fed an HS diet for 4
days. After pretreatment of
glomeruli with the 20-HETE agonist, TGF-01 PaIb only increased from 0.25t0.01
(n-25; 5 rats) to
0.40=L0.01 (n=25; 5 rats).
Example 2
Protection of Kidney from Ischemic Injury by 20-HETE and 20-HETE Agonists
Materials and Methods
[0045] Experiments were performed in male Sprague Dawley rats anesthetized
with
pentobarbital (50 mg/Kg). The kidneys were exposed ;via a midline incision and
the renal arteries
isolated. Adjustable vascular occluders were placed on both the right and left
renal arteries to
completely occlude blood flow to the kidneys for 30 rriinutes. After the
period of complete renal
ischemia, the clamps were removed and the kidneys were reperfused. The
surgical incisions were
closed with 2-0 silk suture and the animals were allowed to fully recover from
anesthesia. Twenty
four hours later, the rats were reanesthetized with pentobarbital and a sample
of blood collected from
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the aorta for measurement of plasma creatinine concentration using an
autoanalyzer. The kidneys
were collected, fixed in 10% formalin solution and paraffin sections prepared
and stained with H and
E to evaluate the degree of tubular necrosis and injury. Three groups of rats
were studied. Group I
rats were treated with vehicle and served as the control animals. Group 2 rats
were treated with an
inhibitor of the synthesis of 20-HETE, HET0016 (5 mg/Kg, sc) 30 minutes prior
to renal ischemia.
Group 3 rats were given a 20-HETE agonist, WIT 003 (10 mg/Kg, sc) by i.v.
injection 30 minutes
prior to renal ischemia.
Results
[0046] Fig. 5 shows the results of the in vivo experiments in which the
effects of HET0016 (an
inhibitor of the synthesis of 20-HETE) and WIT003 (a 20-HETE agonist) on the
degree of renal
injury following ischemia and reperfusion of the kidney were examined. Plasma
creatinine levels
rose from 0.5 to approximately 3.0 mg/d124 hrs after-the kidney of Sprague
Dawley rats was
subjected to 30 minutes of complete ischemia followed by 24 hrs of
reperfusion. The degree of
injury, reflected by the rise in plasma creatinine concentration, was
significantly greater in rats
treated with HET016 (5 mg/Kg, sc), given 30 minutes prior to ischemia.
Administration of WIT003
(1G mg/Kg, sc), 30 minutes prior to reperfusion, significantly reduced the
degree of renal injury
reflected by the rise in creatinine concentration. The rise in plasma
creatinine concentration
following ischemia reperfusion in the control animals is associated with
severe necrosis of the S3
segment of the proximal tubule. The degree of histological damage to this
segment of the renal
tubules is reduced in rats treated with the 20-HETE agonist (data not shown).
[0047] In other experiments, we compared the degree of renal injury seen in
Dahl S rats (20-
HETE deficient strain) subjected to 20 minutes of ischemia reperfusion with
that seen in a congenic
strain of Dahl S rat called 2X4 in which we introduced the CYP4A gene from
Lewis rats that
encodes for the enzyme that produces 20-HETE in the kidney. Transfer of this
gene upregulates the
expression of CYP4A protein in the kidney and the production of 20-HETE in the
kidney. As can be
seen in Fig. 6, transfer of the CYP4A gene from the Lewis rat into the Dahl S
genetic background
also significantly reduced the degree of renal damage as reflected by the
lesser rise in plasma
creatinine concentration 24 hrs after ischemia and reperfusion. This data is
therefore consistent with
the results obtained in the Sprague Dawley rats that upregulation of the
endogenous formation of 20-
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HETE or administration of a 20-HETE agonist protects the kidney against
ischemic renal injury,
while inhibition of the renal formation of 20-HETE exacerbates the degree of-
injury.
[0048] The present invention is not intended to;be limited to the foregoing
example, but
encompasses. all such modifications and variations as come within the scope of
the appended claims.
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